Multiple changesets for widely separated regions

[InsertUser]

It seems to be relatively common to see changesets that appear to cover wide regions of the globe, but when examined actually consist of two unrelated edits in different regions.

A random example of this may be seen here: https://osmcha.mapbox.com/changesets/63732158/

It would be nice if iD were capable of detecting these widely separated edits and encouraging them to be uploaded separately.

The detection for this could be quite coarse as the most egregious of these can be separated by 100 deg of longitude.

My naive suggestion may be:
To run through the coordinates of the nodes of the edited nodes and ways and flag which 10 degree bands of latitude and longitude have edits and which do not (an alternative description may be: to create a histogram in which we only care whether a bar exists, not how high it is).
If there is a band without edits between two bands that do have edits, then this is a sign that the user should be prompted as to whether they really want to upload in one go and provide a means for splitting the upload if desired.

[matkoniecz]

It would be nice if iD were capable of detecting these widely separated edits and encouraging them to be uploaded separately.

do you mean "complain about them and suggest to not do this"? Or "allow to upload part of edits made"?

first is fairly simple, second is likely not worth implementing (see #10292)

[InsertUser]

Preferably allow things to be split after editing, but if that's "not worth implementing" then maybe something like a large annoying banner or overlay that says:

You are about to edit more than 123km away from your last unsaved edit. Please save or discard those edits before continuing.

(with the actual distance rather than a placeholder)

Possibly reusing the formatting used when users need to "zoom in to edit". Some editors don't seem to realise that edits from a previous session can be carried over to their latest one.